Interleukin-6 receptor-interleukin-6 fusion proteins with enhanced interleukin-6 type pleiotropic activities.
An sIL-6R/IL-6 chimera, directly fusing the natural forms of soluble IL-6 receptor and IL-6, as found in human body fluids, was produced in transfected human cells. The secreted p85 glycoprotein was active at a concentration of 120 pM to produce growth-arrest and spindleoid differentiation of murine melanoma F10.9 cells, which do not respond to IL-6 alone. This fusion protein was as active as the yeast-produced p56 fusion protein containing a shortened sIL-6R, linked through a flexible peptide chain to IL-6 (Hyper IL-6). The concentration of Hyper IL-6 needed to arrest the growth of F10.9 cells was much lower than that needed of a combination of IL-6 and sIL-6R, added separately. Hyper IL-6 was also more active than IL-6 in stimulating growth of murine plasmacytoma T1165 cells, the half maximal stimulation being obtained at 2 pM Hyper IL-6 versus 23 pM for IL-6. In order to evaluate the effect of the fused sIL-6R/IL-6 proteins on human hematopoietic primitive progenitor cells, they were added to suspension cultures of CD34+ cells from human cord blood in addition to both flt3/flk2 ligand (FL) and stem cell factor (SCF). Fused sIL-6R/IL-6 produced a marked stimulation of cell expansion and a marked increase in the number of colony forming units when subsequently plated in semi-solid medium with IL-3, GM-CSF, SCF and erythropoietin. Ex-vivo maintenance and expansion of early progenitor cells in bone marrow transplantation protocols may be a potential application for the sIL-6R/IL-6 chimeric glycoproteins.
Chebath
J
J
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
Fischer
D
D
Kumar
A
A
Oh
J W
JW
Kolett
O
O
Lapidot
T
T
Fischer
M
M
Rose-John
S
S
Nagler
A
A
Slavin
S
S
Revel
M
M
D000818:Animals; D001826:Body Fluids / Q000378:metabolism*; D016466:CHO Cells; D002455:Cell Division / Q000502:physiology; D006224:Cricetinae; D006031:Glycosylation; D006801:Humans; D015850:Interleukin-6 / Q000737:chemistry*; D051379:Mice; D010641:Phenotype; D010954:Plasmacytoma / Q000473:pathology; D019947:Receptors, Interleukin-6 / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D019089:Stem Cell Factor / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D011993:Recombinant Fusion Proteins; D019089:Stem Cell Factor